The present invention relates to a feeler device for a copying machine. More specifically, the invention relates to a feeler device of the type comprising:
a support structure movable along at least a first reference axis,
a feeler member supported by the structure so as to be able to effect limited movements relative to the structure along the axis relative to a predetermined rest position, and
detector means for providing electrical signals indicative of the magnitude and direction of the relative movements of the feeler member.
A feeler device of this type is known, for example, from the publication "Gear inspection on a multi-coordinate measuring machine", by H. J. Neumann, a reprint of a paper given during the 5th International Conference on Automated Inspection and Product Control, 12th IPA Meeting, Stuttgart, 24-26th June 1980, edited by Carl Zeiss, Oberkochen, Federal Republic of Germany.
In this known device (see, for example, page 7, FIG. 7 of this publication) the ability of the feeler to move relative to the structure along one axis (for example, a horizontal axis) is achieved by means of the suspension of the feeler from the support structure by means of a pair of rigid blades articulated at their upper ends to the structure and at their lower ends to a plate which is firmly connected to the feeler. The assembly formed by the support structure, the blades and the plate which carries the feeler constitutes a sort of articulated parallelogram whereby a movement of the feeler relative to the support structure along the reference axis results at the same time in a variation in the position of the feeler (relative to the support structure) along the vertical axis.
This characteristic of the known device is a disadvantage which the present invention attempts to overcome.